Reversible engine



. Dec. 25, 1945. w HUBER 2,391,575

REVERS IBLE ENGINE Filed Jan. '7, 1943 Fiel 2 Sheets-Sheet l 3nventor Wn MacchewW. Huber '22 2'5 (Iltorhegs Dec. 25, 1945. M. w. HUBERREVERSIBLE ENGINE Filed Jan. '7, 1945 2 Sheets-Sheet 2 ZSnventor Matchew W. Huber 8B Q din Gltomegs Patented Dec. 25, 1945 2.391.575REVERSIBLE ENGINE Matthew W. Huber, Chicago, 111., assignor, by mesneassignments, to The New York AirBrake Company, a corporation of NewJersey Application January 7, 1943, Serial No. 471,598

'6 Claims.

This invention relates to engines of the expansible chamber type, theword engine" being used in a generic sense to include motors and pumps.

The chief feature of novelty resides in the use of piston type admissionand exhaust valves working in valve chambers which are extensions of thecylinders on which the main engine pistons work. Thus the fluid in anycylinder reacts in opposite directions on the piston and on the pistonvalve of that cylinder, and through the same upon the shaft of theengine. The instantaneous piston displacement in any cylinder is thealgebraic sum of the instantaneous displacements of the piston andpiston valve, but since the valve stroke is comparatively small thisdoes not introduce any seriously disturbing effect.

The advantages of such arrangement are simplicity of construction, andthe ease with which such leakage as occurs may be collected anddischarged.

The device is intended primarily, but not exclusively, for use withliquids rather than elastic fluids. For simplicity, the mechanisms fortranslating reciprocating into rotary motion (and the converse) isillustrated as comprising swash plates, but equivalents can besubstituted.

Reversal may readily be had by "port reversal" i. e. interchange ofinlet and discharge ports.

In the accompanying drawings, the invention is illustrated in itsessential aspects. Refinements such as antifriction bearings, specialseals and the like, though often desirable, are omitted, as theiradoption is a matter of design.

Fig. 1 is an axial section on a plane at a right angle to the mountingface.

Fig. 2 is an axial section on a plane parallel with the mounting face.

Fig. 3 is a fragmentary view, similar to a portion of Fig. 1, showing amodification.

Fig. 4 is an elevation of a piston valve.

Fig. 5 is a section on the line 55. of Fig. 7.

Fig. 6 is an elevation looking from the left end of the device.

Fig. 7 is an elevation at the right end of the device. In this view theoutlines of the cylinder block and cylinder bores are indicated indotted lines.

The housing of the engine is in two parts 6 and I, which mate in aplane, to which the axis of the shaft 8 is normal. The two portions forma housing which is externally of approximately square cross section, butwhich has an internal cylindrical bore. This conformation permits theconnecting screws 9 to be housed in the four corners. It also affordsspace for the inlet and the discharge passages. A conventional circularsealing gasket. I0 is used. This merely prevents leakage of liquid whichis not under pressure.

A cylinder block ll, having an axial central opening slightly largerthan shaft 8, makes a precise slip fit in the cylindrical bore of part Iof the housing and is confined between the annular flanges l2 and I3formed in respective portions of the housing. The cylinder block H has anumber of cylinder bores I5, all at least approximately parallel withthe axis of shaft 8, and arranged in circular series around the shaft.Their angular spacing around the shaft is preferably uniform, as shown,and true parallelism, as shown, is preferred.

The cylinder block is encircled by spaced circumferential port forminggrooves 16 and II which intersect all the bores i5 and preferably extendinward beyond the same, as shown. Either may serve as the inlet port andthe other as the discharge port, and this is true whether the device beused as a motor or as a pump. Interchange of inlet and discharge isrelated to the direction of rotation of shaft in either case, as will beexplained.

Splined to the inner (right hand) end of shaft 8 is aswash plate It!which turns in a, combined thrust and radial bearing l9. Its obliquityis relatively small (say 5) since it serves to actuate the valve pistonsthrough a small reciprocatory range. Keyed to shaft 8 immediately withinportion 6 is the swash plate 2| which turns in a combined thrust andradial bearing 22. It has a relatively larger obliquity, say 25, foritcoacts with the main pistons which should have a substantial range ofreciprocating motion. For a motor, the obliquity may be somewhat largerthan for a pump, and the angle shown is a reasonable compromise value.

The high point of swash plate i8 is displaced (relatively to the axis ofshaft 8) from the high point of swash plate 2| to give the proper phaserelation between the reciprocation of the valves and main pistons.

The main pistons actuated by swash plate 2! are single acting plungers23 each having a head 24 with a universally tiltable thrust surface,here shown as a confined .ball 25 with flat boss 26. Return springs 21(see Fig. 3) are needed if the device is used as a pump. They can beused but are unnecessary if the device is used as a motor. Hence theyare omitted from Figs. 1 and 2 which illustrate the motor embodiment.

The valves, actuated by swash plate [8, are

plungers 28 with counterbores 29 leading from their inner ends. Theyhave heads 3| with ball thrust elements 32 and return springs 33.

Each plunger 28 has an encircling groove 34 which communicates bydrilled ports 35 with its counterbore 29. The valve proper is thatportion of the plunger between the inner end of the plunger and thegroove 34. At mid stroke of the valve this lapsthe two port grooves l6and I1. When liquids are to be handled either in a pump or motor, apositive lap is not desirable. The condition sought is zero lap, withany error on the side of negative lap r clearance. Substantial clearanceis obviously to be avoided because both ports would be opensimultaneously, allowing slip, With elastic fluids, a slight positivelap is often desirable.

The shaft 8 may drive or be driven through any suitable connections.Formed in the corners of housing portion 1 are a passage 36 whichcommunicates with port grooves l6 and a passage 31 which communicateswith port groove l1.

Either passage 36 or 31 may be the supply connection and the other thedischarge connection. If the engine be used as a motor, interchange ofthe ports 36 and 31 as between supply and exhaust will cause reversal ofdirection of rotation of shaft 8 (commonly called port reversal, in theengine art). The engine will operate as a. pump if the shaft 8 be drivenin either direction, but the direction of flow depends on the directionof drive.

The port 38 typifies a, relief passage to carry leakage from the camspaces within the housing and thus'prevent development of fluid pressurewithin such spaces. The port may lead to any drain. If the engineoperates as a pump, connection could be to the suction line, and if as amotor, then to the exhaust line. Obviously, if a port reversing valveis'used, account must be taken of the changing characteristics-oftheports between the reversing valve and the engine. Various expedientswill suggest themselves,

In its broadest aspects, the invention contemplates the use of a pistonand a piston valve to define an intervening working space in a cylinder,regardless of the relative positions of cylinder and shaft andregardless of the form of mechanical connections between the shaft andpiston and between the shaft and valve. The valve connections may differin type from the other.

However, the scheme ofiers peculiar advantages where a circular seriesof parallel cylinders,

encircles the drive shaft. A swash plate is convenient for each drive,because it gives harmonic motion (or a close approximation thereof).However, a swash plate is merely a special type of cam and other camscan be used, as well as other drives familiar in the pump art for usewith this typical cylinder and shaft arrangement.

I claim:

1. In an expansible chamber engine, the combination of a rotar shaft;any number of expansible chamber units, each comprising an open endedcylinder having supply and exhaust ports, a main piston closing one endof the cylinder, and a distributing valve of the piston type closing theother end of the cylinder, whereby an intervening working space isformed, the piston valve serving to connect said supply and exhaustports alternately with the working space; and mechanical connectionsbetween the shaft and main pistons and between the shaft and pistonvalves so arranged that as the shaft rotates the main pistonsreciprocate and the piston valves reciprocate with a shorter strokethan. and each valve reciprocates substantially out of phase with, thecorresponding main piston.

2. In an expansible chamber engine, the combination of a rotary shaft;any number of expansible chamber units, each comprising an open endedcylinder having supply and exhaust ports, the axis of the cylinder beingsubstantially parallel with the "axis of said shaft, 9. main pistonclosing one end of the cylinder, and a distributing valve of the pistontype closing the other end of the cylinder, whereby aninterveningworking space is formed, the piston valve serving to connect,said supply and exhaust ports alternately with the working space; andmechanical connections between the shaft and main pistons and betweenthe shaft and piston valves, said connections comprising cams on theshaft respectively related with followers on the pistons and on thepiston valves, and so formed that as the shaft rotates the main pistonsreciprocate and the piston valves reciprocate with a shorter strokethan, and each valve reciprocates substantially 90 out of phase with,the corresponding main piston.

3. In an expansible chamber engine, the combination of a rotary shaft;any number of expansible chamber units, each comprising an open endedcylinder having supply and exhaust ports, the axis of the cylinder beingsubstantially parallel with the axis of said shaft, a main pistonclosing one end of the cylinder, and a distributing valve of the pistontype closing the other end of the cylinder, whereby aninterveningworking space is formed, the piston valve serving to connect said supplyand exhaust ports alternately with the working space; a swash platefixed on the shaft and arranged to coact with the main pistons; and asecond swash plate of less obliquity than the first fixed on the shaftwith its high point displaced with reference to the shaft axis 90 fromthe first swash plate, and arranged to coact with the piston valves.

4. In an expansible chamber engine, the combination of a rotary shaft;any number of expansible chamber units, each comprising an open endedcylinder having supply and exhaust ports, the axis of the cylinder beingsubstantially parallel with the axis of said shaft, a main pistonclosing one end of the cylinder, and a distribut ing valve of the pistontype closing the other end of the cylinder, whereby an interveningworking space is formed, the piston valve serving to connect said supplyand exhaust ports alternately with the working space; mechanicalconnections between the shaft and main pistons so arranged that as theshaft rotates the pistons reciprocate; and a cam on the shaft arrangedto reciprocate the piston valves with an amplitude sufiicient to tionsand having combined radial and thrust bearings alined with each otherand in opposite ends of the housing; cams, one sustained by androtatable in each of said bearings; a shaft mounted to turn with bothsaid cams and withdrawable from at least one thereof; a cylinder blockpositioned between the portions of the housing interposed between thecams, and having a bore to receive the shaft, a surrounding circularseries of cylinder bores extending from end to end of the block, and twoencircling port grooves which intersect the cylinder bores; a series ofpistons, one piston working in one end of each of said bores andcoacting with one of said earns; a series of piston type distributingvalves, one valve working in the other end of each of said bores andcoacting with said port grooves, and with the other of said cams; andmeans associated with said housing for establishing independent fluidflow connections with the port grooves in the cylinder block.

6. The combination of a cylinder block having a cylinder bore extendingfrom end to end thereoi and a pair of spaced ports communicating withsaid bore; a piston reciprocable in one end of said 'bore; a piston typevalve reciprocable in the other end of said bore whereby an interveningworking space is defined between the piston and piston valve, saidpiston valve being counterbored from its inner end and having anencircling groove in communication with said counterbore, the portion ofthe valve between its inner end and said groove serving to controltheports in the cylinder block; a rotatable shaft; and connectionsbetween the shaft and the piston and between the shaft and distributingvalve serving to constrain them to reciprocation in a definite phaserelation, the amplitude of reciprocation of the distributing valve beingsmall as compared to the amplitude of reciprocation of the piston.

MATTHEW w. HUBER.

